METHOD FOR SMOOTHING OPTICAL MEMBER FOR EUVL AND OPTICAL MEMBER FOR EUVL HAVING SMOOTHED OPTICAL SURFACE

摘要

Disclosed is a method for smoothing an optical surface of an optical member for EUVL, said optical surface having recessed defects.  In the method, an optical surface having recessed defects, which is an optical surface of an optical member for EUV lithography (EUVL) composed of a quartz glass which is mainly composed of SiO2 while containing TiO2, is irradiated with a laser oscillating at a wavelength at which the optical member for EUVL has an absorption coefficient of not less than 0.01 µm-1 at a fluence of 0.3-1.5 J/cm2 in an atmosphere having a water vapor partial pressure of not more than 3.6 mmHg, whereby the optical surface of the optical member for EUVL is smoothed.